Synchronous electric motor structure



Feb. 20, 1940. A. B. POOLE 2,191,221

SYNCHRONOUS ELECTRIC MOTOR STRUCTURE Filed July 16, 1938 2 Sheets-Sheet l 1 540 ,1W 5 YM Feb. zo, 1940. A E. OLE y 2,191,221

SYNCHRONOUS ELECTRIC MOTOR STRUCTURE Filed July 16, 1938 2 Sheets-Sheet 2 Patented Feb. 2.0, 1940 UNITED STATES `2,191,221 SYNCHBONOUS ELECTRIC MOTOR STRUCTURE Arthur B. Poole, Bristol, comi., signor to 'nie Company, Bristol, Conn., a corporation of Connecticut Applicants July ls, 193s, serial 10.219.493 solaims. iol. liz-21s) E. Ingraham This invention relates to improvements in synchronous electric motor structures of the type primarily designed for the propulsion of clocks and other time-instruments, thoughuseful in a wide variety of other situations. More particularly, the present invention is concerned with the rotor-structure and the operatively-connected parts of such a synchronous electric motor structure. i

l@ @ne of the objects of the present invention is to provide a superior synchronous electric motor structure wherein the thorough and complete lubrication of the rotor-unit is assured.

Another object of the present invention is to i5 provide a superior construction and arrangement of parts in a synchronous electric motor structure whereby the rotor-unit may be assured of an adequate supply of lubricant by means of a reduction-train connected 29 the said rotor-unit.

A further object of the present invention is to provide a superior synchronous electric motor structure having simple, reliable and long-wearing means for supporting the rotor-unit thereof.

5 With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a rear-face view of a synchronous electric'motor structure constructed in accordance with.v the present invention;

Fig. 2 is an edge view thereof;

Fig. 3 isa transverse sectional view taken on the line 3 4 of Fig. 1;

Fig, 4 is a fragmentary transverse sectional View taken on the line l-I of Fig. 1;

Fig. 5 is a view of the motor structure in rear elevation, substantially corresponding to Fig. 1 save that the bearing-plate and reduction-gear train have been removed to expose the drivepinion;

unit;

Fig. 7 is a transverse sectional view taken on Fig. 8 is a view in side elevation of the unitconlprising the center-shaft and the pinion and gear-wheel carried thereby; and

Fig. 9 is a view in central longitudinal section oi a modiiied form of rotor unit.

to and propelled by- Fig. 6 is a view in side elevation of the rotor- PATENT OFFICE The particular synchronous electric motor structure herein chosen for the purpose of illustrating the present invention includes a rotorunit, generally designated by the reference characier lo, and including a rotor-hub Il, which is 5 preferably formed of brass or the like, and upon which is rigidly mounted a pair of corresponding but oppositely-facing cup-shaped rotor-elements I2-I2', preferably formed of permanentmagnet material such as hardened steel or its equivalent. The said cup-shaped rotor-elements I2--I2 are spaced from each other by a salientpoled rotor-unit I3 which may be conveniently made of soft iron or other non-permanent magnetic material. The cup-shaped rotor-elements i2-I2 are substantially smooth upon their outer peripheries and are not provided with geometrically-salient poles, but owing to their permanent-magnet character, are adapted to receive magnetic spottings, so to speak, which i0 will be impressed upon them by the adjacent salient poles of a stator-structure to be more fully hereinafter described.

The rotor-hub II is, as shown, provided at its forward end with a sleeve-like bearing-portion 25 hi which bears upon the adjacent surface oi a center-arbor I5 to be more fully hereinafter described. The rear end of the rotor-hub II is formed with a rearwardly-extending sleeve-like portion IE having an axial passage I'l extending 80 therethrough, as well as through the main portion of the adjacent rotor-hub Il proper, as is especially well shown in Fig. 3. The internal ,diameter of the axial passage I1, just referred to, is considerably larger than the external di- $6 ameter of the center-arbor I5 which extends therethrough, andreceives at its rear end, with a drive-lit, the forward end of a drive-pinion I8 which latter bears with freedom for rotation up- .on the rear portion of thecenter-arbor I5. As o the drive-pinion I8 is thus installed in the rear end of the sleeve-like portion I 6 of the rotorhub II, the slots between the gear-teeth of the said drive-pinion provide a plurality of oil-passages through which lubricant may pass to the o interior of the rotor-hub for distribution between the contiguous bearing-surfaces of the latter and the center-arbor I5.

The rotor-unit I0, above described, is circumferentially enclosed within a stator-structure l0 which is shown and described in detail in my co-pending application, Serial No. 177,839, filed December 3, 1937.

The stator-structure. above referred to, includes a cup-shaped pole-unit, generally designated by the reference character I 9, land a complementary disk-like pole-unit, generally designated by the reference character 20, both of which units are composed or suitable magnetic vmaterial such, for instance, as'soft iron, silicon steel, or the like.

In the instance shown, the cup-shaped poleunit I9 is of laminated character and includes a rearwardly-extending annular iiange or skirt 2| and an end-wall 22 extending perpendicularly with respect to the axis of the center-arbor By reference to Figs. 3 and 4, it will be noted' that the iiange or skirt 21 of the inner cupshaped member 24 is of lesser depth than the adjacent ange or skirt 25 of the outer cupshaped member 23, to thus provide for the mounting of the disk-like pole-unit 2!! in a manner as will presently appear.

The disk-like pole-unit 20 comprises outer and inner disks 29 and 3U respectively, both of which iit within the otherwise open end of the cupshaped pole-,unit I9 in such manner that the inner disk 30 rests against the rear edge of the 'flange or skirt 21 of the inner cup-shaped member 24. y

For the purpose of rigidly securing the poleunits I9 and 20 together, the skirt or flange 25 of the outer cup-shaped member 23 of the said cup-shaped pole-unit I9 is provided with a plurality of nibs or indents 3I which extend over the outer disk 29 of the disk-like pole-unit 20.

Projecting rearwardly from the end-wall 22 of the cup-shaped pole-unit I9 is an annular-lyarranged series of bar-like salient poles 32 formed of suitable magnetic material and arranged in three (more or less) relatively-closely-spaced pairs around the center-arbor I5, before referred to. As will be noted by reference to Fig. 5 of the drawings, the pairs of salient poles 32 have relatively-wide gaps between them, into which forwardly project a corresponding number of pairs of salient poles 33 which extend forwardly from the disk-like pole unit 20. The spacing ofl the salient poles 32 and 33 is such that when they are all assembled, the pairs of salient poles 32 alternate in an annular direction with the pairs of salient poles 33.

The salient poles 32 and 33 correspond to each other in size and form to facilitate manufacture and to render the said salient poles interchangeable one for the other. Each of the said salient poles 32 and 33 is of substantiallyrectangular form in cross-section throughout the major portion of its length and is provided at one end with a cylindrical shank 34 for extensionV through a suitable perforation in the particular pole-lmt I9 or 29 of'which it may form a part. Preferably and as shown, each shank 3 4 s headed over as at 35 against the outer face of the adjacent pole-unit, to firmly anchor the parcular salient pole in place.

At its end opposite its shank 34, each salient pole 32 and 33 is formed with a cylindricallyvcontoured stabilizing-tenon 3B for the purpose as Will be presently described.

Positioned against the inner face of the endwall 22 of the cup-shaped pole-unit I9 is a shading-disk 31 formed of copper or other suitable high-electroconductive material and provided with an annular series of substantially-rectangular perforations 38, each of which is adapted in shape and location to snugly t over the baseportion of one of the bar-like salient poles 32 of the pole-unit I9. Each alternate one of the perforations 38 is intersected by a radial slot 39 which thus serves to interrupt the iiow of induced current in the portion of the shading-disk 31 surrounding the particular salient pole. The remaining three perforations 38 are not intersected by slots, but the material of the shadingdisk 31 which surrounds them is uninterrupted and provides a complete electrical path for the 2* iiow of induced currentaround -the particular three salient poles 32 extending therethrough.

From'the foregoing, it will be seen that each alternate one of thessalient poles 32 is shaded, so

to speak, by the shading-disk`31, so that the 2l magnetic flux in these particular salient poles will lag with respect to the magnetic ux in the remaining three unshaded salient poles 33, so as to produce a rotating-held effect. In addition to the perforations 38 and the radial slots 39, 3l

the shading-disk 31 is provided with an annular series of sockets 40 into each of which projects the stabilizing-tenon 36 of one of the salient poles 33 (Fig- 3).

rprovided with an annular series of substantiallyrectangular perforations 42 which respectively snugly iit over the base-portions of the bar-like salient poles 33 of the said disk-like pole-unit 29. Like the shading-disk 31, the shading-disk.` II is provided with radial slots 43 which inter"-` sect respectively each alternate one of the perfo-.-v rations 42. fThe remaining the "perforations 42 are not'intersected by slots and are therefore electrically continuous, so that a rotating-held eect is achieved in the salient poles 33 considered as a group, in a manner similar to that described in connection with the group of salient poles 32.

The shading-diskv 4I, in addition to its perforations 42 and its radial slots 43, is provided with an annular sexies of sockets Minto each of which projects the stabilizing-tchou `315 of one 0i the salient poles 32 of the' cup-shaped poleunit I9.

Surrounding the salient poles 32 and 33 is a ring-like energizing-coil 45 which is thus located axially intermediate the end-wall 22 of the cupshaped pole-unit I9 and the disk-like pole-unit Zlwhich together constitutetwo complemental spaced-apart magnetic portions from which the salient poles 32 and 33 respectively pnoject. The said energizing-coil 45 is provided with two leadwires 46 and 41 which are adapted to be connected by any suitable means to a source of` alternating or other sinuous current for the purpose of energizing the said coil.

Returning now to the center-arbor I."` upon which the rotor-unit I l rotates, it'will be noted by-reference to Fig. 3 that the said center-arbor bears at its forward end in the shading-disk 31 and bears at its rear end in va substantially-triangular bearing-plate 48 which is held in spaced relationship rearwardly of the disk-like pole-unit 28 by means of a plurality of pillars 48 to which latter the said bearing-plate is removably at-v tation by'virtue of its being supported for rotation, as above described, in both the shadingdisk 3.1 and the bearing-plate 48.

The .drive-pinion I 8 of the rotor-unit I0 meshes into and drives a gear-wheel 5I mounted for rotation upon a stud. 52 and rigidly carrying a pinion 53. The said pinion 53 meshes into and drives a gear-wheel 54 which is staked or otherwise rigidly secured to the center-arbor I5 at a point intermediate the drive-pinion I8 and the inner face of the bearing-plate 48.

The extreme rear portion of the center-arbor I5 which projects beyond the rear of the bearingplate 48 has staked or otherwise secured to it a pinion 55 meshing into and driving a gear-wheel 58 (Figs. l to 4 inclusive) which is staked or otherwise rigidly secured to the rear end of a power-output shaft 51.

The rear end of the power-output shaft 51 is journaled in the bearing-plate 48 whilevits front portion is journaled in the forward portion of a bearing-bushing 58 rigidly mounted in the endwall Z2 of the cup-shaped pole-unit I9. The bearing-bushing 58 is provided with a relativelyslender rearwardly-projecting tubular oil-guard 59 having an internal diameter considerably larger than the diameter of the power-output shaft Si and extending into a position closely adjacent the forward face of the shading-disk 4I, as is especially Wellshownin Fig.y 4. To prevent undue axial displacement of the said poweroutput shaft 51, the same is provided with a collar S0 located intermediate the bearing-plate 48 and the disk-like pole-unit 28.

The entire motor structure above described is adapted to be enclosed in any suitable oil-tight housing such, for instance, as the housing illustrated in my copending application above referred to, so that as the gear-train already described revolves, a supply of lubricant may be constantly picked up by the said gear-train.

In Fig. 9 is illustrated a modified form of rotorunit which includes a pair of oppositely-facing cup-shaped rotor-elements 8I-8I corresponding to the rotor-elements I2-I2 before v described and like the same spaced ,from each other by a salient-poled rotor-element here designated by the .reference character 82 and corresponding to the rotor-element I3 before described.

The rotor-elements 8I.-8I and 82 are rigidly attached to a composite rotor-hub generally designated by the reference character 83 and including a relatively-long and slender sleeve 84 having a bearing-passage 85 of relatively-small diameter at its rear end and having themajor portion of its length provided with an interior oil-chamber 58. The said oil-chamber 66 is of an internal diameter sufciently large to clear a shaft having a diameter corresponding to the bearing-passage 85 and to provide a reservoir for oil or other lubricant. Forced with a drive-fit into the forward end of the oil-chamber 88 in the rotor-hub 88 is a bearing-bushing 81 having an axial bearmgll mmm or s substantial'- ly corresponding to the diameter of the bearingpassage 85 before referred to.

lThe sleeve 84 of the rotor-hub 83 is provided with an integral forwardly-facing stop-shoulder 88 and fitted over the forward portion of the said sleeve with a drive-fit and in engagement with,

the said stop-shoulder 88 is' a bushing 10 having an annular outwardly-projecting flange 1I. The rotor-elements 8Il8l and 82 are'centrally apertured to fit over the body-portion of the said bushing 18 and are clamped in place against the vflange 1I thereof by means of a collet 12 forced onto the forward end ofthe body-portion of the bushing 1I).y In this manner the rotor-elements 8I-8I and 82 are rigidly attached to the sleeve 84 for rotation therewith.

Cut into the periphery of the rear portion ofthe sleeve 84 is a plurality of longitudinally-extending grooves 13 resulting in the formation of a plurality of gear-teeth 14 designed and adapted to function as a drive-pinion in a mannercorresponding to that described in connection with the drive-pinion I8 of the structure of Figs. 1 to 8 inclusive.

The grooves 13 which result in the formation of the gear-teeth 14 above described extend sufficiently rearwardly so as to break through, so

-to speak, into the interior of the oil-chamber 88 and provide a plurality of oil-passages 15 interconnecting each groove 13 with the said oilchamber 88. l

By means of the construction and arrangement of parts wherein the rotor-hub I I or its equivalent is provided with a drive-pinion or the like organized with it in such manner as to provide for the ingress of lubricant into the interior of the said rotor-hub, the smooth chatterless running of the rotor-unit is assured over long periods of use.

Furthermore, by organizing the parts so that I the rotor-unit revolves upon the independentlyrotatable center-arbor I5 or its equivalent Within the encircling energizing-coil 45, a very compact and rugged construction results wherein the reduction-train is compacted and the over-all size of the motor structure is kept at a minimum.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

l. An electric motor structure, includingl in combination: a field-structure having salient v poles; a rotor-supporting arbor; a rotor-unit located for rotation in the magnetic field of the said vfield-structure and comprising a tubular hub-portion having an axial passage therethrough for the reception of the said rotor-supporting arbor; and a drive-pinion projected at one end of and rotatable with the said hub-porhub-portion independently of the axial passage in the said drive-pinion to thereby admit lubricant to the interior of the said hub-portion.

2. An electric motor structure including in combination: a iield-structurehaving salient poles; a rotor-supporting arbor; a rotor-unit located for rotation in the magnetic-held of the said eld structure and comprising, a tubular hubiportion having an axial passage therethrough for the reception of the said rotor-supporting arbor; and a drive-pinion having gear-teeth thereon and coupled to the said hub-portion, the said drivepinion being projected at one end of said hubportion and also having an axial passage registering With the axial passage of said hub-portion for extension of the said rotor-supporting arbor beyond the axial passage of the hub-portion and into and through the axial passage of said drivepinion, and the gaps between the gear-teeth of the said drive-pinion communicating with the axial passage in the said hub-portion to supply lubricant thereinto. g

3. An electric motor structure, including in combination: a field-structure having salient poles; .a' rotor-supporting arbor; and a rotorunit located for rotation inthe magnetic-field of the said field-structure and comprising, a tubular hub-portion having an axial passage therethrough for the accommodation of the said rotorsupporting arbor and having a contracted portion bearing. upon the said rotor-supporting arbor and having an opposite enlarged end clearing the said rotor-supporting arbor; and a. drive-pinion secured within the enlarged end of the axial passage in the said hub-portion and having an axial passage therethrough, the said drive-pinion having the Wall-surface of its axial passage bearing upon the said rotor-supporting arbor, and the said drive-pinion having external grooves communicating with the axial passage in the said enlarged end of the hub-portion independently of the axial passage in the said drive-pinion to thereby admit lubricant to the interior of the said hub-portion.

4. An .electric motor structure, including in combination: a field-structure having salient poles; a rotor-supporting arbor; and a rotor-unit located for rotation in the magnetic-held ofthe said held-structure andcomprising, .a tubular hub-portion having an axial passage therethrough for the accommodation of the said rotorsupporting arbor and having one contracted portion bearing upon the said rotor-supporting' arbor and having anV opposite enlarged end to clear the said rotor-supporting arbor; and a drive-pinion secured within the enlarged end of the axial passage in the rsaid hub-member and having an axial passage therethrough, the said drive-pinion having the wallsurface of its axial passage bearing upon `the said rotor-supporting arbor, and the grooves between the teeth of the said drivepinion communicating with the-enlarged end of the axial passage in the said hub-portion to supply lubricant iihercinto.

5. An electric motor structure, including in combination: a field-structure having salient poles; a rotor-supporting arbor; and a rotor-unit comprising, a magnetic-portion rotatable adjacent the salient poles of the, said held-structure, a. tubular hub-portion Vof non-magnetic material having an axial passage therethrough for the re.-

Y ception of the said rotor-suDpOrting arbor; and

a 'drive-pinion projected at one end of and rotatable with the said non-magnetic hub-portion, the said drive-pinion also having. an axial passage registering with the axial passage of said hub-portion for extension of the said rotor-supporting arbor beyond the axial passage of `the K hub-portion and into and through the axial passage of said drive-pinion, and the. said drive-pinion having external grooves communicating with the axial passage in the said non-magnetic hubportion independently of the axial passage in the said drive-pinion to thereby admit lubricant to the interior of the said non-magnetic hub-portion.

6. An electric motor structure, including in combination: a field-structure `having salient poles; a rotor-supporting arbor; and a rotor-unit comprising, a magnetic-portion vrotatable adjacent the salient poles of the said held-structure, a tubular hub-portion-of non-magnetic material having an axial passage therethrough for the reception of the said rotor-supporting arbor, and a drive-pinion having gear-teeth thereon and coupled to the said non-magnetic hub-portion, the said drive-pinion being projected at one end of said hub-portion and also having an axial passage registering with the axial passage of s aid hub-portion for extension of the said rotor-supporting arbor beyond the axial passage of the hub-portion and into ,and through the axial passage of said drive-pinion, and the gaps between the gear-teeth of the said drive-pinion communicating with the axial passage in the said non-magnetic hub-portion to supply lubricant thereinto.

'7. An electric motor structure, including in combination: a held-structure having salient poles; a rotor-supporting arbor; and a rotor-unit comprising, a magnetic-portion rotatable adjacent the salient poles of the said field-structure, d y a' tubular hub-portion or non-magnetic material having an axial passage therethrough for the reception of the said rotor-supporting arbor and having a contracted portion bearing upon the said rotor-supporting arbor and also having an opposite enlarged end clearing the said rotor-supporting arbor; and a drive-pinion having an axial passage receiving the said rotor-supporting-arbor and bearing upon the said arbor, the said drive-pinion secured Within the enlarged end of thev axial passage in the said non-magnetic hubportion, and the said drive-pinion having external grooves communicating with the axial `passage in the said non-magnetic hub-portion independently of the axial passage in the said drivepinion to thereby admit lubricant to the interior of the said non-magnetic hub-portion.

'8. An electric motor structure, including in combination; a held-structure having salient poles; a rotor-supporting arbor; and a rotor-unit comprising, a, magnetic-portion rotatable'adjacent the salient poles of the said Vheld-structure,

larged end of the' axial passage in the said non-v magnetic hub-portion, the gaps between the gear-teeth of the said drive-pinion communicating with the enlarged end of the axial passage in the said non-magnetic hub-portion to supply lubricant thereinto..

ARTHUR B. POOLE. 

